On my last trip I noticed the Baja Box being pulled away from the vertical bolts causing the thin aluminum sheet to bend and paint to crack. It seems with my bikes mounted on top of the rack, and with the second bike positioned close to but still on the outer edge of the box, this would create enough leverage that the metal would fatigue around the 1" washer.
I corrected this with already made 3" square 1/4" billet aluminum. By increasing the surface area by 9x, and reducing the force by 81x, the unit is held nicely. I would also consider replacing the bolts such that there is only an inner bolt. As stock, someone could just take the plastic cover off, unbolt the box and take the bikes and contents. Then again, it would be just as easy to pry off the door, unbolt the box and take the unit.
Any thoughts on a better bolting system?